Mercury switch



May 21, 1940. I J WORTH 2,201,754

MERCURY SWITCH Fliled July 17, 1959 INVENTOR.

ATTORNEYS.

Patented May 21, 1940 UNITED STATES PATENT OFFICE 4 Claims.

This invention relates to a safety switch, or an automatically operated switch for mounting in the usual ignition circuit of a motor vehicle, aeroplane, boat or similar carrier, the primary ob- 5 ject of the invention being to provide a switch which will immediately open the circuit to the ignition mechanism, in case of a collision of such a nature as to cause the vehicle to be tilted or turned over.

Another object of the invention is to provide a device of this character which may be manually operated to open the ignition circuit of the vehicle and lock the ignition circuit in such open position, preventing the use of the vehicle by unauthorized people.

With the foregoing and other objects in view, which will appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein described, may be made within the scope of what is claimed, without departing from the spirit of the invention.

Referring to the drawing:

Figure l is a vertical sectional view through a switch constructed in accordance with the invention, and illustrating the switch in its closed position.

Figure 2 a vertical sectional view illustrating the switch in its open position, breaking the cir cuit which it is used.

Referring to the drawing in detail, the body portion oi the switch is indicated generally by the reference character ii, the body portion being constructed oi insulating material to insulate the body portion irom the vehicle or carrier with which the device used.

CED As clearly shown by the drawing, the body por tion includes an upper cup-shaped compartment t which is iced with external threads to accommodate the threads of the cap "I? which closes the upper side of the compartment.

- d9 Formed integral with the body portion and ex tencling into the cup-shaped compartment t, is an annular flange 8, the upper end thereof being flared as at Q, the edge 01 the flared portion of the flange being extended downwardly at Ill to 58 guard against the mercury, which is used in the switch, from passing upwardly into the flared portion of the flange, when the mercury passes from the center of the body portion, to the space between the annular flange 8 and inner surface ct the cup-shaped compartment.

The base of the body portion, is indicated at l I, and extends downwardly an appreciable distance, the base being formedwith a solid portion l2 formed with an opening to receive the lock valve l3, which is of the usual and well known con- 5 struction, and operated by the key M. Secured to the lock valve I3, is a shaft l5 that is provided with a right angled end portion 16 which pivotally connects with the link l1, that in turn has pivotal connection with the piston l8, which is of a 10 diameter to move within the central opening I! of the body portion.

The upper surface of the piston is recessed, providing a compartment for the quantity of mercury, indicated at 20, and due to the construcll tion, it will be seen that when the piston 18 moves downwardly to the limit of its downward movement, the upper edge thereof will lie in a line with the bottom of the compartment 6. Openings 2| are formed in the annular flange 8, and permit mercury which may find its way into the compartment, to flow back into the recessed portion of the piston IE3.

li'he reference character 22 indicates one wire of the ignition circuit, the wire being connected as to the piston at 23, Another wire of the ignition system is indicated at it and extends through the cap or cover i oi the device, wherelt connects with the contact member 25 which is provided with a plurality of pointed extensions to no that extend into the mercury contained in. the recessed portion of the piston it, completing the circuit through the piston and wire 52?.

' From the foregoing it will be obvious that when the key M has been turned to move the piston It so to the position as shown by: Figure 2 of the drawing, the ignition circuit will be broken and it will be impossible to operate the motor of the motor vehicle or carrier with which the switch is used.

When the switch is in its active position as in shown by Figure l, and the carrier with which it is used, tilts laterally, beyond a predetermined point, due to a collision, it is obvious that the mercury will. flow over the flared portion 9 of the flange 8, and pass into the space between the to flange t and compartment ti. The circuit between the wires, 22 and 2 is now broken, and the motor with which the ignition circuit is used, will immediately stop, eliminating any possibility of fire, due to the current passing through the ignition system.

It will further be seen that due to the construction of the disk, formed at one end 01 the contact member 25, as well as the construction of the compartment 6, the mercury in the comparta ment 8 will be thrown therefrom, in case of a collision. When the mercury moves from the cupshaped compartment 6, the circuit to the ignition is immediately broken.

What is claimai is:

1. A mercury switch comprising a body portion, an annular flange having a flared end, formed within the body portion, an electrode extending into the body portion, a piston operating within the body portion and having a recess, mercury within the recess, means for moving the piston whereby the mercury is brought into contact with the electrode, a wire connected with the piston completing a circuit through the piston and mercury, said mercury adapted to flow over the flared end of the flange breaking the circuit between the electrode and piston when the body portion tilts a predetermined degree, said flange having openings normally closed by said piston, and said openings adapted to permit the mercury to flow into the recess of the piston from the space between the flange and body portion.

2. A mercury switch comprising a body portion, an annular flange within the body portion and having openings at the base thereof, a piston movable within the body portion, said piston having a recess in the upper end thereof, mercury in said recess, an electrode extending into the body portion, means for moving the piston whereby the mercury is brought into contact with the electrode completing a circuit, and an electric wire connected with the piston and in circuit with the mercury and electrode.

3. A mercury switch comprising a body portion havinga chamber formed therein, an annular partitioning member within the chamber, a piston movable within the body portion and ex- .the base thereof whereby mercury may flow from the compartment into the recess, and said piston normally closing the openings when the piston is in its active position.

4. A mercury switch comprising a body portion having a central bore, a piston operating within the bore, said body portion having a compartment, said piston having a recess formed in one end thereof, mercury in the recess, an electrode extending into the body portion and adapted to be engaged by the mercury in the recess, completing a circuit through the piston and electrode, said piston adapted to move to a position with the upper end thereof flush with the bottom of the compartment whereby mercury may flow from the compartment into the recessed portion of the piston, and an electric wire connected with the piston in circuit with the piston and electrode, through the mercury.

JOSEPH B. WORTH. 

